This invention relates to regulation of the flow and pressure of the respiration gas in a respirator, and concerns a flow and pressure measuring device (arranged in the immediate vicinity of the patient connection) for determining the flow and pressure of the respiratory gas and converting the magnitudes measured into electrical signals, as well as a valve arrangement (arranged between the respiration gas source and the measuring device) for controlling the flow and pressure of the respiration gas. Further, the invention concerns as electronic regulator for carrying out this regulation.
The common respirators are controlled systems, i.e. their functional sequence is governed by rigidly specified input magnitudes. A group of known respirators includes the so-called pressure-controlled systems, with which respiratory gas is delivered under pressure to the patient, wherein a control valve interrupts the delivery of the respiratory gas if a certain specified pressure is built up in the line leading to the patient.
A further group includes the so-called volume-controlled systems, by which an amount of the respiration gas measured according to volume is delivered to the patient. Both types of respirators have at least the one disadvantage, which is principally inherent to all controlled systems, that they cannot react to compensate for changes in the lung mechanics not detectable in advance.
There have also previously been suggested automatically controlled respirators which, however, are not suitable for a wide routine employment in hospitals for various reasons. One such reason, for example, is that the measurement of the regulatory magnitude, there are necessary complicated devices which in addition are on the one hand expensive and on the other hand susceptible to disorders.
With respect to this problem, hitherto the possibilities of offering an automatic regulation have, to the disadvantage of the patient, not been pursued.